I don't think so? Both the house router and the cellular hotspot have the same IP address. They are both connected to the indigo machine, so I'm not sure which one is replying. My indigo machine had different addresses depending on which one it's using. 192.168.1.10 on the home network. 192.168.1.2 on wifi(cellular).
I'm currently trying to figure out if I can Ping via MAC address since the router and hotspot have different mac addresses (but same LAN address).
From terminal, when I "arp -a" I see both 192.168.1.1 entries. I see the MAC address for the hotspot, the MAC address for the Router is (Incomplete).
In my head, this may not be doable. If home internet is down, the router is still up, so I should still be able to successfully ping everything on my home network.
Edit: I'm trying to see If I can change the LAN settings of the hotspot to 192.168.2.1 to better differentiate the networks. However, online or offline, I think I'll still have the same issue, both devices will still be connected to the Indigo machine regardless of their connection to the rest of the world.
I'm still tinkering as I'm typing this. Hopefully it won't do anything horrible. (I'm always nervous when I start entering random stuff from google searches in terminal) So if there is a global internet blackout.... sorry about that.
Edit2: Tried a different approach, instead of a hotspot device, I tried an extra cell phone connected via USB, It connected with the IP address 172.20.10.4. This gives me an option over the wifi route.... "Disable unless needed" So maybe use a successful ping to the 172.20.10.4 address = ethernet down.
Another alternative is to maybe use network speed as an online sensor to determine where my internet is coming from. Both the hotspot device and the cell phone are 4G LTE with a weak signal running about 2-10 Mbps download versus home network average at 180-200 Mbps.